Hi all: We are using XP Pro SP3 here and about every two weeks someone complains that their PC is off the network (I do not know how many are not complaining). This happens both while the people are working and when the PCs are idle (the shortest idle time has been about 1 hour the longest about 3).
All the PC's have the "turn off the NIC to save power" disabled, Hibernation is disabled and I don't see standby being a problem as it has happened while people are working.
Nothing is showing up in the Events Log.
These are all Lenovo Laptops and Desktops, we are on a 1Gb network, we are using SBS 2003 R2 as our DC, all the other servers are 2003 or 2003 R2 (none of the servers have ever shown this issue.
The PCs are all up to date on the software and firmware. These are all physical connections and no wireless.
So far to solve the problem I have had to Reboot, or Disconnect and Reconnect the NIC, or Disable and Re enable the NIC. Sometimes it will show little or no connectivity, overtimes it just won't access the network.

Can you describe what your setup & what you mean in a little more detail?

1.) Are you using roaming profiles? No.

2.) Are users able to access any network resources? Yes but only the main SQL server via their SQL desktop engine. OR they had just connected that way when they noticed the problem with something else.

3.) Are you using mapped drives that show as disconnected? No until you try to access them.

We are using Lenovo T61 and T500 Laptops and ThinkCenter Desktops. The network is all HP gigabit switches. All the servers they seem to be having connection issues with are HP blade servers (the SBS 2003 R2 and the rest are SBS 2003 R2).
I have replaced network cables and tried different ports on the switches.
This does not seem to be a repeating per user but it is happening more often. Most of the users involved are the out of office types so their laptops have been on other networks.

WOW! Talk about timing, it just happened again. The guy has been out of the office for a week. He DID send and receive email, he DID connect with the SQL server. He COULD not print to a network printer. He tried to fix it by logging in and out. I forced his system to sync and now it is working. He got the little icon of computer with a little i on it.

Widows SBS 2003 Server. How many of these servers are Domain Controllers? If it's more than one, that's the problem.

SBS Server will shut down Kerberos, the default secure network service if it is aware of another 2003 SBS DC. Kerberos will work fine with other 2003 Servers, running 2003 Standard or Enterprise as a Member Server.

Widows SBS 2003 Server. How many of these servers are Domain Controllers? If it's more than one, that's the problem.

SBS Server will shut down Kerberos, the default secure network service if it is aware of another 2003 SBS DC. Kerberos will work fine with other 2003 Servers, running 2003 Standard or Enterprise as a Member Server.

This is behaviour by design.

Best Regards
Just

Only the SBS Server is the DC no other DC's. DNS is handeled by the SBS server too.

Are the external Users coming in with a stale IP Address, allocated from their Home Routers DHCP?

You said originally:

"So far to solve the problem I have had to Reboot, or Disconnect and Reconnect the NIC, or Disable and Re enable the NIC. Sometimes it will show little or no connectivity, overtimes it just won't access the network."

Are the external Users coming in with a stale IP Address, allocated from their Home Routers DHCP?

You said originally:

"So far to solve the problem I have had to Reboot, or Disconnect and Reconnect the NIC, or Disable and Re enable the NIC. Sometimes it will show little or no connectivity, overtimes it just won't access the network."

Best Regards
Just

That may be the case, but shouldn't DHCP force a new IP address uppon connecting to the network?